Hi: need some help from you experienced electricians. What I'm trying to do is hook a coal furnace up to my oil furnace. My questions is there a relay or some type of switch that if one furnace calls for the circulating pump to run and the other also wants to send elect to the pump. I need a either or type of switch, so if the pump is running from one furnace and the other call for the pump to run the electric can not get to the pump till the other one is not calling for it to run, So the pump is not getting elect from two sources. This is not a standard hookup so bear with me. If you can help thanks.

Hi: need some help from you experienced electricians. What I'm trying to do is hook a coal furnace up to my oil furnace. My questions is there a relay or some type of switch that if one furnace calls for the circulating pump to run and the other also wants to send elect to the pump. I need a either or type of switch, so if the pump is running from one furnace and the other call for the pump to run the electric can not get to the pump till the other one is not calling for it to run, So the pump is not getting elect from two sources. This is not a standard hookup so bear with me. If you can help thanks.

What difference does it make if one switch kicks on, and the other one kicks on? You are tripping the same motor.

I'm not sure on this that is why I asked, put it like this, if I had a motor and had a extension cord plugged in and hooked to the motor and then took another extension cord and plugged it into another outlet what would happen, would there be a direct short.